In 1955, a young stills photographer embarked on directing a feature film, although she claimed scarcely ever to have been to the cinema. She was Agnès Varda and the film was La Pointe Courte, which was described by Georges Sadoul, the influential film critic, as “the first film of the Nouvelle Vague”. Its interplay between conscience, emotion and the real world make it a direct antecedent of Alain Resnais’ Hiroshima Mon Amour. Varda, who has died aged 90, was henceforth considered the “mother of the French New Wave”.

La Pointe Courte, edited by Resnais, was shot in a small fishing village in the south of France, and tells two stories concurrently, the themes never intermingling: the struggle of the fishermen against the economic domination of the big combines, and the story of a young man from the village who comes home with his Parisian wife in an attempt to save his marriage.

The film set the pattern for Varda’s future films, both fiction and documentaries, which she wrote, produced and directed: the artistic composition, the personification of objects, the binary structures, the manipulation of space and time, the proximity of realism and fantasy and the correlation of individual subjectivity to societal objectivity. It was also her stated belief that the film-maker should exercise as much freedom as a novelist that became a mantra for the New Wave directors.

When, in 2017, she was awarded an honorary Oscar, special mention was made of her “compassion and curiosity [that] inform a uniquely personal cinema”.

She was born Arlette Varda in the Ixelles quarter of Brussels, the daughter of Eugène Varda, an engineer, and Christiane (nee Pasquet). When she was 18, Arlette legally changed her name to Agnès. She studied literature and psychology at the Sorbonne in Paris, art history at the École du Louvre, and photography at night school. She then worked as a stage photographer for Jean Vilar’s Avignon festival and his Théâtre National Populaire in Paris.

After her first feature, Varda turned to making short films for the French tourist board. However, these were no ordinary travelogues. They showed her keen eye, poetic vision and ironic sense of humour. O Saisons, O Chateaux (1957) was about the castles of the Loire valley; L’Opéra Mouffe (1958) was a lyrical evocation of the Parisian street-market in Rue Mouffetard as seen through the eyes of a pregnant woman (Varda was pregnant at the time); and Du Côté de la Côte (1958) was a fresh and irreverent approach to the French Riviera.

With the feature Cléo from 5 to 7 (1962), Varda took her place among the New Wave directors who had recently made such a splash. The film, divided into chapters using Tarot cards, which symbolise fate, observes two hours in the life of a nightclub singer as she waits for the medical verdict on whether she is to live or die. Every trivial incident takes on a new significance for her, and Paris is seen as if for the last (or first) time. Jean Rabier’s camera captures the sheen of the city so brilliantly that the anxiety of the protagonist (the coolly beautiful Corinne Marchand) is slightly minimised.

In 1962, Varda was invited to Cuba, where she took more than 4,000 black-and-white still photos, resulting in Salut Les Cubains, in which they were cut together. Commenting in 2004, Varda said that “this cheerful film reminds us of the energy, the hope and enthusiasm that really did exist in 1962”.

The advertisement-style prettiness of Le Bonheur (Happiness, 1965) created an ambiguity and ironic reflection on the film’s title. It tells of a carpenter (Jean-Claude Drouot) who wants his wife to accept that he can be happily married and love his mistress. The wife kills herself and he lives happily ever after with his mistress and children. The film’s amorality provoked controversy, added to which the male lead’s real family played his wife and children. Varda called Le Bonheur, which won the special jury prize in Berlin, “essentially a pursuit of the palette”.

She followed it with Les Créatures (1966), which again had twin stories, the birth of a novel and the birth of a child. The characters are all pawns in a fascinating chess game played on an outsize board. However, its utilisation of an inside-outside plot that mingles real and unreal events was lost on many, and the film failed at the box office. Consequently, Varda, finding it difficult to put together another film in France, made her next film, Lions Love (1969), in Los Angeles, at the same time that her husband, Jacques Demy, whom she had married in 1962, was making Model Shop.

Very much a reflection of the times, Lions Love featured the director Shirley Clarke playing an avant-garde director in Hollywood shacking up with James Rado and Gerome Ragni (co-authors and stars of Hair) and Viva, one of the stars of Andy Warhol’s Factory. In a Pirandellian moment, when Clarke cannot go through with a suicide, Varda steps in and acts the part herself. On television the assassination of Robert Kennedy is playing.

It was almost 10 years before Varda would make her next feature, One Sings, The Other Doesn’t (1977), a film which came out of her involvement with the women’s movement. Taking Simone de Beauvoir’s maxim that “one isn’t born a woman; one becomes one” as her theme, the director presents two friends of different temperaments and backgrounds representing aspects of feminism from 1962 to 1976.

Although the film was rather ideologically overloaded and romantic about the pleasures of pregnancy – the one sings a song about it called Beautiful to Be a Balloon – it was rare to see female characters achieving independence and fulfilment on screen. As Varda said: “I wanted to portray the happiness of being a woman.” It was another eight years before Vagabond (1985), one of her most successful features. It begins with the body of a young woman (Sandrine Bonnaire) found frozen to death in a ditch. Various witnesses tell of their encounters with her and how she gave up an office job for life on the open road.

A telling study of an aimless existence upon which the director imposes a rigorous form, it is constructed in a series of sequences, some lasting a few seconds. It is to the credit of both Varda and Bonnaire that such an unsympathetic central character manages to reach tragic stature as she moves further and further into degradation against a cruel but beautiful wintry landscape.

In the long gaps between her fiction features, Varda made imaginative and moving documentaries, cine-poetic essays, among her very best work. In The Gleaners and I (2000), Varda speaks to an eclectic range of people who “glean”, or collect, from the ground. “To bend down is not to beg,” she narrates. This was followed by the equally enthralling The Gleaners and I: Two Years Later (2002). Ydessa, The Bears and Etc (2004) is a meditative masterpiece in which Varda explores the nature of photography through an exhibition in which every photo contains a teddy bear.

Agnès Varda, centre in black, in The Beaches of Agnès (2008), which features a tribute to her husband Jacques Demy. Photograph: Alamy

The magical Visages Villages (Faces Places, 2017), nominated for an Oscar as best documentary feature, follows Varda and JR, the enigmatic street artist and photographer, around rural France, interviewing and photographing people with tales to tell in order, as she says, “to meet new faces so I don’t fall down the holes in my memory”.

Varda made three films dedicated to the memory of Demy, who died of Aids in 1990: The Young Girls Turn 25 (1993), a nostalgic piece about the making of Demy’s The Young Girls of Rochefort; The World of Jacques Demy (1995), a personal biography consisting of interviews and film clips; and Jacquot De Nantes (1991), a poignant portrait of a film-maker as a young man. There is also a loving tribute to Demy in The Beaches of Agnès (2008), a poetic autobiographical documentary.

Varda is survived by Mathieu, her son with Demy, and Rosalie, a daughter from an earlier relationship, with the stage director Antoine Bourseiller.